1. Field of Invention
The present invention is related to a manual stretcher.
2. Related Prior Art
Referring to FIG. 5, a conventional manual stretcher includes a frame 1. The frame 1 includes a bracket (not numbered) formed thereon. The bracket can be securely attached to an external structure (not shown) so that the conventional manual stretcher can be retained in position in operation. The frame 1 includes two lateral plates. A hole 5 is defined in each of the lateral plates of the frame 1. A hollow shaft 4 is inserted through the holes 5. A slot is defined in the hollow shaft 4 for receiving a portion of a strip of work to be stretched (not shown). A ratchet 2 is soldered to an end of the hollow shaft 4 and a joint 3 is soldered to another end of the hollow shaft 4. A crank (not shown) can be inserted in two holes defined in the joint 3. Thus, the crank can be operated in order to rotate the hollow shaft 4 for stretching. Soldering causes roughness on the hollow shaft 4 Roughness prevents smooth rotation of the hollow shaft 4 on the frame 1. Grinding is often taken so as to eliminate such roughness. Thus, the difficulty in finishing is increased and time for fabrication is extended. Furthermore, soldering gives rise to flaws in structure and/or errors in dimension. In addition, points subject to soldering are vulnerable to concentration of stress and often become points of fracture.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in fabrication and use of the above-mentioned conventional manual stretcher.
It is an objective of the present invention to provide a manual stretcher that can be fabricated precisely.
It is another objective of the present invention to provide a manual stretcher that can be fabricated easily.
It is another objective of the present invention to provide a manual stretcher that can be fabricated quickly.
It is another objective of the present invention to provide a manual stretcher that is strong in structure.
In the present invention, a manual stretcher includes a frame, a shaft, a ratchet, a claw, a joint and a crank. The frame includes two lateral plates, an intermediate plate interconnecting the lateral plates and a hole defined in each of the lateral plates. The frame can be attached to an external structure so that the manual stretcher can be retained in position in operation. The shaft includes a slot defined therein for receiving a portion of a strip of work to be stretched. The shaft is inserted through the holes. The ratchet is mounted on an end of the shaft. The claw is pivotally mounted on one of the lateral plates of the frame for engagement with the ratchet. The joint is mounted on another end of the shaft for engagement with the crank for rotation of the shaft.
The shaft may include two halves. The ratchet may include two meniscus holes defined therein for receiving the halves of the shaft. The joint may include two meniscus recesses defined in an end thereof for receiving the halves of the shaft.
Each of the halves of the shaft may include a stop formed on an end thereof for abutting the ratchet.
The stop formed on each of the halves of the shaft may be a curved ridge.
Each of the halves of the shaft may include a hole defined in an end thereof. The joint may include two opposite pin-receiving holes defined in a periphery thereof. A pin can be inserted in the holes defined in the halves of the shaft and the pin-receiving holes defined in the joint, thus securely mounting the joint on the halves of the shaft.
The joint may include a partition separating the meniscus recesses from each other. A pin-receiving hole may be defined in the partition of the joint.
The frame may include a bracket formed on the intermediate plate for attachment to the external structure.
The joint may include a number of crank-receiving holes defined in a periphery thereof for receiving the crank.
In an aspect of the present invention, the halves of the shaft are hollow. More particularly, each of the halves of the shaft is made of a metal strip by folding.
In another aspect of the present invention, the halves of the shaft are solid.
Other objectives, advantages, and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the attached drawings.